Under body cleaning and salt/chemical protection

[Bowruss]

Helllo all.

It's coming round again so I'm thinking about a routine for keeping my under body clean.  I  have no after market stuff on and it's as it left the factory. 

I've  heard cautionary tales about power washing and hose, etc damage so I just need to keep it washed off every say month when they bring out the road chemicals.

Anybody got their own experiences? 

I'm  not really up to a lot of bending to get under the car and I think car wash guys usually couple the under spray jets with those killer brushes.

Anyway, what do you all do if anything?

[TonyHSD]

Hi, 

the best way I found for myself is to wash with hose and water or jet spray with suitable attachments., just spray from a safe distance.
You can use tfr or Snow Foam or one after the other, or simply just pure water. 
Another good idea is to drive on motorways when is heaven rain spring time after the salt been cleaned away. 
And last but not least, best to never use any corrosion protection applied, these are nothing but trouble and can also invalidate your warranty. 👍

[Bowruss]

Thanks Tony.  I'll  see how I go on with mains pressure and a wand thing that will give an aim underneath due to its flexible nozzle end.  

I worry that my Karcher may be too powerful except  on the  less power setting as I can't  see the various connections that could be disturbed by a too powerful jet.

Good point about  the after market coatings.  They are seductive and well  promoted. 

[oldcodger]

Our Nilfisk pressure washer has a car kit that contains 2 special nozzles, both producing lower pressure, one for normal bodywork paint and one thats got an angled head for doing under the car without having to bend right down.

Do Karcher do a similar thing or  if a third party do such fittings ?

[Basil-BarryC]

2 hours ago, oldcodger said:

Our Nilfisk pressure washer has a car kit that contains 2 special nozzles, both producing lower pressure, one for normal bodywork paint and one thats got an angled head for doing under the car without having to bend right down.

Do Karcher do a similar thing or  if a third party do such fittings ?

I seem to remember Karcher did manufacture an accessory for under car cleaning which fitted most Karcher power washers. IIRC Search for Karcher UnderChassis Cleaner 

[AisinW]

For UK and most part of western europe, the snow is mild. Pressure washing the underbody in a car wash is the best and cheapest way to keep it rust free. £1 for 2 minutes of pressure washing is enough after snowy days with salts on the roads.

If you have severe salt application issues, like in the northern part of Scotland, you can apply fat-base spray. It works well and does not trap moisture, unlike heavy rubberized coatings.  Lanolin/wool wax base is easy to apply and safe to rubber and joints. You can get it from Cosmoline, Woolwax, Fluid Film spray.

The rubberized heavy coating is only good when the car was new but not for a used car that has already some dings and surface rust.  If you apply heavy coating on already rusted surface, it will only accelerate the rust tremendously.

[JasonM]

During the summer when the car is dry and clean I’ve used a light mist of Bilt Hamber Dynax UC on bare and painted metal around the sub frames and suspension.  Just avoid getting it near the brake discs.   I doubts it lasts for years but keeps the salt at bay for a winter.   

https://www.parkers.co.uk/car-advice/car-care/best-underseal/